coolpina
Newbie level 1
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Hi!
I'm solving an excercise from Razavi's book (Fundamentals of microelectronics).
The problem is:
"A n-type piece of silicon with a lenght of 0.1 um and a cross area section of 0.05 um x 0.05 um sustains a voltage difference of 1V.
Doping level is 10^17 cm^-3.
(a) Calculate the total current flowing through the device at T = 300K."
I calculated from equation:
Jtot = un * E * n * q + up * E * p * q
from ni^2 = n*p I found p = 1,17 * 10^3 cm^-3, so part up* E * p * q is neglible
Jtot ≈ un * E * n * q = 5,4 uA
Then, there is:
"(b) Repeat (a) for T = 400K assuming for simplicity that mobility does not change with temperature. (This is not a goog assumption)"
But whats the difference? for T = 400K, p = 1,38 * 10^8 so its still neglible when n = 10^17
Probably im doing something wrong - but what? Please, give me some clues
I'm solving an excercise from Razavi's book (Fundamentals of microelectronics).
The problem is:
"A n-type piece of silicon with a lenght of 0.1 um and a cross area section of 0.05 um x 0.05 um sustains a voltage difference of 1V.
Doping level is 10^17 cm^-3.
(a) Calculate the total current flowing through the device at T = 300K."
I calculated from equation:
Jtot = un * E * n * q + up * E * p * q
from ni^2 = n*p I found p = 1,17 * 10^3 cm^-3, so part up* E * p * q is neglible
Jtot ≈ un * E * n * q = 5,4 uA
Then, there is:
"(b) Repeat (a) for T = 400K assuming for simplicity that mobility does not change with temperature. (This is not a goog assumption)"
But whats the difference? for T = 400K, p = 1,38 * 10^8 so its still neglible when n = 10^17
Probably im doing something wrong - but what? Please, give me some clues